1. Field of the Invention
The present invention relates to an electro acoustic system and more particularly, to the built-in test and calibration method of such system, which enables the electro acoustic system to be self-tested and corrected at any place with ease.
2. Description of the Prior Art
With the development of various communication technologies, communication devices such as telephone have become part of our everyday life. Because regular home telephones are cheap, people usually buy a new one to replace the failed units. However, if one expensive communication device, for example, conference station has a communication problem or noises, the maintenance fee is very high, and the related examination apparatus is also expensive. It is a heavy cost burden to the user either to repair the conference station by oneself or to send the conference station to the distributor for repair.
According to conventional techniques, the internal circuit of an expensive communication device must be tested during the semi-finished stage of the product, and the product is assembled and packed after test. However, some conditions such as signal interference and system instability may occur during assembly process or after a long period of use due to ageing or variation of parts and circuits. In this case, an expensive external test apparatus shall be used, or the product shall be detached for internal circuit examination, thereby resulting in waste of cost and manpower.
Further, when the sampling test of one particular lot of products shows a high failure rate, the products of the whole lot must be wholly examined. It requires much time and labor to examine the products of the whole lot because of the accumulated man-hours and occupation of expensive test apparatus involved. In this case, the production line will be interrupted, and the manufacturing cost will be greatly increased.
Therefore, it is desirable to provide an electro acoustic system built-in test and calibration method that eliminates the aforesaid problems.